Motivated by the recent muon $g-2$ data, we study the lepton flavor violating (LFV) $l\to l^{\prime }\gamma$ and $Z\to l{\overline{l}}^{\prime }$ ($l$, $l^{\prime }=e$, $\mu$, $\tau$ decays with $l\ne l^{\prime }$) in a scalar leptoquark model. Leptoquarks can produce sizable LFV $l\to l^{\prime }\gamma$ decay rates that can be easily reached by present or near future experiments. Leptoquark masses and couplings are constrained by the muon $g-2$ data and the current $l\to l^{\prime }\gamma$ bounds. We predict $\mathrm{Br}(Z\to {\tau }^{\mp }{e}^{\pm })$ reaching the present limit (${10}^{-5}$) and $\mathrm{Br}(Z\to {\mu }^{\mp }{\tau }^{\pm })$ reaching $2\times {10}^{-8}$, which will be accessible by future linear colliders, whereas, the current bounds on LFV impose very strong constraints on the $\mathrm{Br}(Z\to {\mu }^{\mp }{e}^{\pm })$ and the ratio is too low to be observed in the near future.

• Received 30 July 2008

DOI:https://doi.org/10.1103/PhysRevD.78.075025